Involuntary function problems linked to worse life quality

Study examines autonomic nervous system dysfunction in NMOSD patients

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by Andrea Lobo |

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Problems in the autonomic nervous system (ANS), which regulates involuntary bodily processes such as heart rate, blood pressure, and digestion, are very frequent among people with neuromyelitis optica spectrum disorder (NMOSD), a study has shown.

All 80 NMOSD patients in the study experienced ANS-related symptoms, and a greater burden of these symptoms, particularly orthostatic intolerance, was associated significantly with worse quality of life. Orthostatic intolerance refers to a feeling of dizziness after standing up due to a sudden blood pressure drop.

These findings add to previous studies showing that ANS problems in NMOSD patients significantly affect their quality of life.

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The study, “Impact of the autonomic dysfunction on the quality of life in people with NMOSD and MS: an international cross-sectional study,” was published in the journal Multiple Sclerosis and Related Disorders.

NMOSD is an autoimmune disease that primarily leads to inflammation of the spinal cord and optic nerve, which relays signals between the eye and the brain. This leads to symptoms related to the control of muscles and vision.

An increasing number of studies have pointed out ANS-related symptoms in people with NMOSD, including gastrointestinal dysfunction, bladder disturbances, and orthostatic intolerance.

People with multiple sclerosis (MS), another autoimmune disease that affects the brain and spinal cord, also experience substantial ANS dysfunction.

“Although there is a lack of data regarding the relation between ANS dysfunction and the quality of life in both people with MS (pwMS) and NMOSD (pwNMOSD), it can be hypothesized that ANS abnormalities might substantially impact the quality of life in these patients,” the researchers wrote.

Now, a team of researchers in Serbia, Croatia, and Montenegro investigated the burden of symptoms affecting the ANS, and their impact on the quality of life of 80 NMOSD patients and 100 MS patients. Participants were followed across three national referral neurological clinics.

The mean age of NMOSD patients was 47.1 years, and most (82.5%) were women. They were living with the disease for a mean of 6.8 years, and the majority (61.3%) had at least one relapse in the previous year.

There were no significant differences between NMOSD and MS patients in terms of sex, age, disease duration, and disability, as assessed with the Expanded Disability Status Scale.

Evaluating autonomic nervous system dysfunction

ANS dysfunction was evaluated using a self-administered questionnaire called Composite Autonomic Symptom Score-31 (COMPASS-31). It assesses autonomic symptoms across six domains: orthostatic intolerance; vascular problems; abnormalities in the production of bodily fluids, such as sweat, tears, and saliva; gastrointestinal symptoms; bladder issues; and pupil dilation deficits.

COMPASS-31 scores range from 0 to 100, with higher scores indicating more severe symptoms.

Results showed that ANS dysfunction was detected in all people with NMOSD, and nearly all with MS (97%). MS patients had a higher median COMPASS-31 score than those with NMOSD (11.8 vs. 9.4), but this difference did not reach statistical significance.

The burden of orthostatic intolerance and pupillomotor symptoms was significantly higher among MS patients than NMOSD patients, with a significantly higher proportion of MS patients affected by orthostatic intolerance (41% vs. 15%).

The MS Quality of life-54 questionnaire

Patients’ health-related quality of life was assessed with the Multiple Sclerosis Quality of life-54, a self-reported questionnaire that evaluates both the physical and mental quality of life domains.

People with NMOSD had significantly higher scores in the mental quality of life domain than those with MS, particularly regarding emotional well-being, cognitive functioning, and health distress, indicating a better quality of life among NMOSD patients. No significant group differences were observed for the physical domain.

Moreover, in both patient groups, worse overall ANS dysfunction was associated significantly with worse quality of life in both mental and physical domains.

Researchers also assessed depression using a self-scored questionnaire called Beck Depression Inventory. In both groups of patients, the mean score was not indicative of depression, and there were no significant differences between the groups.

Further analyses showed that among NMOSD patients, lower orthostatic intolerance burden, less disability, and lower depression scores were independent predictors of a better physical and mental quality of life.

Age also was found to be an independent predictor of NMOSD patients’ physical quality of life. Similar results were obtained for people with MS, in addition to total COMPASS-31 scores.

“In line with our data, in the only investigation related to the impact of ANS symptoms burden to the quality of life in NMOSD, it has been recently demonstrated that the COMPASS-31 score was independently correlated with all the domains of the quality of life measured by [a generic questionnaire],” the researchers wrote.

Autonomic nervous system dysfunction increases burden

Overall, most patients with either NMOSD or MS have a considerable burden caused by symptoms affecting the ANS, which are associated significantly with lower quality of life.

“Further investigations are warranted in order to optimize treatment interventions in MS and NMOSD,” the researchers wrote.